Authorities insist the child, who has been taken out of school, came nowhere near carrying out such an attack, having no access to weapons and no means to get them. But they are treating the case seriously, even though school administrators told parents last week "no present threat exists."

The incident sent shockwaves through the quiet community of Wall Township, N.J., an enclave off the Garden State Parkway in Monmouth County.

Word of the alleged threat spread after the local district issued a notice to parents, fearing that word of the investigation would leak out through rumors that could make the situation sound worse than it was.

In an interview with ABC News, Monmouth County prosecutor Christopher Gramiccioni said the event was "being blown out of proportion."

Gramiccioni said the student, whose name has been withheld because of his age, had a "fantastical mind" and simply mused on his home computer that he would like to harm about 40 people.

The student listed the first names of other children "probably in his class," said Gramiccioni. But he also named such public figures as President Obama. "That shows how fantastical and not a well-planned or thought-out idea this was," Gramiccioni said.

"He was just conveying things running through his mind. It's problematic. He's going to need help. But there was no danger to his classmates, his school, his family."

The school district notified the parents of the students named.

Interim schools Superintendent Stephanie Bilenker wrote in a letter to parents that the district and local police "have already and will be continuing to take additional steps, beyond normal security measures, to ensure the safety of the students involved and every other student in the school system."

A law-enforcement source told ABC News that the child had a history of emotional and psychological problems, and will not be allowed to return to school this year.

No charges have been filed yet, although the fifth grader is expected to face juvenile charges of communicating "terroristic threats" or similar charges, said Charles Webster, a spokesman for the Monmouth County prosecutor.

"We're in a society where people are wary of things like Newtown," said Webster.